Flexible Heart Valve and Holder Therefor

ABSTRACT

A highly flexible tissue-type heart valve is disclosed having a structural stent in a generally cylindrical configuration with cusps and commissures that are permitted to move radially. The stent commissures are constructed so that the cusps are pivotably or flexibly coupled together at the commissures to permit relative movement therebetween. The stent may be cloth-covered and may be a single element or may be made in three separate elements for a three cusp valve, each element having a cusp portion and two commissure portions; adjacent commissure portions for each pair of adjacent stent element combining to form the stent commissures. If the stent has separate elements their commissure portions may be pivotably or flexible coupled, or may be designed to completely separate into independent leaflets at bioresorbable couples. The cloth covering may have an outwardly projecting flap that mates with valve leaflets (e.g., pericardial leaflets) along the cusps and commissures. A connecting band may be provided that follows the cusps and commissures and extends outwardly. The valve is connected to the natural tissue along the undulating connecting band using conventional techniques, such as sutures. The connecting band may be a cloth-covered silicon member and attaches to the underside of the valve at the cusps to provide support to the stent and to the outer side of the valve at the commissures. The connecting band includes commissure portions defining generally axial gaps that help permit flexing of the valve.

RELATED APPLICATIONS

The present application is a continuation of U.S. application Ser. No.12/717,278 filed Mar. 4, 2010, which is a continuation of U.S.application Ser. No. 12/557,404 filed Sep. 10, 2009, which is acontinuation of U.S. application Ser. No. 12/391,212 filed Feb. 23,2009, now abandoned, which is a continuation of U.S. application Ser.No. 12/188,826 filed Aug. 8, 2008, now abandoned, which is acontinuation of U.S. application Ser. No. 10/729,035, filed Dec. 5,2003, now U.S. Pat. No. 7,481,838, which is a continuation of U.S.application Ser. No. 09/847,930, filed May 3, 2001, now U.S. Pat. No.6,736,845, which is a continuation-in-part of U.S. application Ser. No.09/332,759, filed Jun. 14, 1999, now U.S. Pat. No. 6,558,418, whichclaims priority under 35 U.S.C §119(e) to provisional application No.60/117,445, filed on Jan. 26, 1999, the disclosures of which areexpressly incorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates to prosthetic heart valves, and, moreparticularly, to a highly flexible prosthetic tissue valve andassociated connecting band or sewing ring.

BACKGROUND OF THE INVENTION

Prosthetic heart valves are used to replace damaged or diseased heartvalves. In vertebrate animals, the heart is a hollow muscular organhaving four pumping chambers: the left and right atria and the left andright ventricles, each provided with its own one-way outflow valve. Thenatural heart valves are identified as the aortic, mitral (or bicuspid),tricuspid and pulmonary valves. The valves of the heart separatechambers therein, and are each mounted in an annulus therebetween. Theannuluses comprise dense fibrous rings attached either directly orindirectly to the atrial and ventricular muscle fibers. Prosthetic heartvalves can be used to replace any of these naturally occurring valves,although repair or replacement of the aortic or mitral valves are mostcommon because they reside in the left side of the heart where pressuresare the greatest. In a valve replacement operation, the damaged leafletsare excised and the annulus sculpted to receive a replacement valve.

The four valves separate each ventricle from its associated atrium, orfrom the ascending aorta (left ventricle) or pulmonary artery (rightventricle). After the valve excision, the annulus generally comprises aledge extending into and defining the orifice between the respectivechambers. Prosthetic valves may attach on the upstream or downstreamsides of the annulus ledge, but outside of the ventricles to avoidinterfering with the large contractions therein. Thus, for example, inthe left ventricle a prosthetic valve is positioned on the inflow sideof the mitral valve annulus (in the left atrium), or on the outflow sideof the aortic valve annulus (in the ascending aorta).

Two primary types of heart valve replacements or prostheses are known.One is a mechanical-type heart valve that uses a ball and cagearrangement or a pivoting mechanical closure to provide unidirectionalblood flow. The other is a tissue-type or “bioprosthetic” valve which isconstructed with natural-tissue valve leaflets which function much likea natural human heart valve, imitating the natural action of theflexible heart valve leaflets which seal against each other to ensurethe one-way blood flow.

Prosthetic tissue valves comprise a stent having a rigid, annular ringportion and a plurality of upstanding commissures to which an intactxenograft valve or separate leaflets of, for example, bovine pericardiumare attached. The entire stent structure is typically cloth-covered anda sewing ring is provided around the periphery for attaching to thenatural annulus. Because of the rigidity of the material used in thestent and/or wireform, conventional valves have a diameter that isminimally affected by the natural motion of the heart orifice. In theaortic position, the commissures extend in the downstream direction aspaced distance from the walls of the downstream aortic wall. Movementof the aortic wall or sinuses does not directly affect movement of thecantilevered commissures, though fluid flow and pressures generated bymovement of the walls ultimately does cause the commissures todynamically flex to some extent (i.e., they are cantilevered downstreamin the aorta). Because of the inherent rigidity in conventional heartvalves, the natural dilatation of the annulus is restricted, imposing anartificial narrowing of the orifice, and increasing the pressure droptherethrough.

Accordingly, there is a need for a more flexible heart valve thatresponds to the natural motions of the annulus and downstream vesselwalls.

SUMMARY OF THE INVENTION

The present invention allows the prosthesis to follow the aortic wallmotion as well as that of the annulus during systole and diastolephases, thus reducing the loss in pressure caused by restriction of suchmotions. The solution is a heart valve having a plurality of leaflets,preferably three, directly sutured to the aortic wall, replacing thenative valve.

The present invention provides a heart valve including a flexiblewireform or stent that allows relative cusp movement or pivoting. Thecontinuous maintenance of leaflet orientation at the commissuresprovides durability and predictability. Though the leaflets are notwholly independent, they are allowed to move in regions of greatestanatomical motion.

The present invention differs in another respect from bioprosthetictissue valves of the prior art because it does not include aconventional sewing ring with attendant rigid stent. Alternatingperipheral cusps and commissures of the prosthetic valve are attached tothe annulus region and the sinus region of the ascending aorta of thehost (in the aortic valve version), downstream from the location of thenatural leaflets (typically excised).

In accordance with one aspect of the present invention, a prostheticheart valve is provided including a flexible, generally cylindricalstent having alternating cusps and commissures. A plurality of flexibleleaflets is attached to the stent so as to form a one-way valve withinthe cylinder. A flexible band is attached along the stent and has a freeedge extending away from the stent along the alternating cusps andcommissures for connecting the heart valve to an anatomical orifice.

Another aspect of the present invention is a highly flexible heart valveincluding a stent/leaflet subassembly having a peripheral stent and aplurality of leaflets disposed therewithin. The stent/leafletsubassembly defines alternating cusps and the commissures. A connectingband is attached to the stent/leaflet subassembly and follows thealternating cusps and commissures. The band includes a free edgeextending from the stent for connecting the heart valve to an anatomicalorifice.

In a still further aspect of present invention, a prosthetic heart valvecomprises a plurality of flexible leaflets, each having an arcuate cuspedge and a coapting edge. The heart valve includes a stent with aplurality of cusps connected to each other at upstanding commissures togenerally define a substantially cylindrical volume therebetween. Theleaflets are attached to the stent within the cylindrical volume and thecusps are free to move with respect to one another about thecommissures.

In another embodiment, the present invention provides a prosthetic heartvalve comprising a stent having a plurality of stent members adjacentlydisposed generally around a circle to define a substantially cylindricalvolume therebetween. The stent includes a plurality of alternating cuspsand commissures. Preferably, the stent members each have a cusp and twocommissure regions, with adjacent commis sure regions of the stentmembers together defining each of the commissures of the stent. Thestent members may be coupled together to pivot or flexibly move withrespect to one another. The coupling may be permanent, or may comprise abio-resorbable structure that permits the stent members and associatedleaflets to move independently from one another.

Desirably, the stent of the prosthetic heart valve of the presentinvention is configured to permit the cusps and commissures to moveradially in and out. In one embodiment, the stent comprises a clothcovered rod-like structure. The cloth covering closely surrounds thestent and includes a flap projecting therefrom substantially the entirelength of the cusps and commissures for connecting the stent to both theflexible band and the leaflets. The band preferably comprises asuture-permeable inner member, such as silicone, covered by cloth. Thecusps of the stent may be pivotally or flexibly coupled to each other atthe commissures. Preferably, the stent comprises separate cloth-coveredstent members that each define a cusp region and two commissure regions,adjacent commissure regions of the stent members together defining eachof the commissures of the stent. The commissure regions of the separatestent members desirably remain spaced apart, with the leaflets extendingtherethrough to be attached between the cloth covering and the outerconnecting band. In this manner, the leaflets are connected to separatestent members, and not to each other to facilitate flexing of the valve.

In another aspect of the present invention, a holder is provided formounting the flexible heart valve. The holder includes a central hubwith a plurality of radially outward upper legs, and a plurality oflower legs angled downward and outward. The upper and lower legs areadapted to connect to the alternating cusps and commissures of aflexible valve so as to maintain the position of the valve duringimplantation.

The present invention further provides a combination of a flexibleprosthetic heart valve and a rigid holder. The flexible heart valveincludes alternating cusps and commissures in a generally cylindricalconfiguration adapted to move radially in and out with respect to oneanother. The holder includes structure for maintaining a fixed shape ofthe flexible prosthetic heart valve during implantation.

In a still further aspect of the present invention, a heart valveleaflet is provided comprising a flexible, planar body having an arcuatecusp edge terminating at outer tips. The planar body includes a coaptingedge that is defined by two relatively angled lines joined at an apexdirected away from the cusp edge midway between the two tips. Desirably,the leaflet is made of pericardial tissue.

The present invention further provides a method of implantation of aheart valve, including the steps of: providing a flexible heart valvehaving alternating cusps and commissures in a generally cylindricalconfiguration and adapted to move radially in out with respect to oneanother; attaching a holder to the valve that restricts relativemovement of the cusps and commissures; positioning the heart valve inproximity to an anatomical orifice; implanting the heart valve; and,disconnecting the holder from heart valve.

The present invention provides a holder for a heart valve including aflexible stent that allows relative cusp movement or pivoting. Thecontinuous maintenance of leaflet orientation at the commissuresprovides durability and predictability. Though the leaflets are notwholly independent, they are allowed to move in regions of greatestanatomical motion. The heart valve may be highly flexible and include astent/leaflet subassembly having a peripheral stent and a plurality ofleaflets disposed therewithin. The stent/leaflet subassembly definesalternating cusps and the commissures. A connecting band may be attachedto the stent/leaflet subassembly and follows the alternating cusps andcommissures. The band may include a free edge extending from the stentfor connecting the heart valve to an anatomical orifice.

In one aspect of the invention, a holder for attaching to and holding aflexible heart valve is provided. The heart valve is of the type thathas multiple leaflets joined together at a periphery of the valve atvalve commissures that are generally axially aligned and evenly disposedabout a valve axis, the valve commissures are located between adjacentcurvilinear valve cusps along the periphery of the valve. The holdercomprises a plurality of cusp supports arranged around an axis tocontact the heart valve generally along the valve cusps, and a pluralityof commissure supports connected to and intermediate each two cuspsupports and arranged to abut the valve commissures. The commissuresupports are desirably radially flexible enabling the valve commissuresto be flexed inward while in contact with the holder commissuresupports. For example, the commissure supports may be made of Nitinol.Preferably, at least one leg extends radially inward from a cusp supportto a location surrounded by the plurality of cusp supports, and morepreferably multiple legs extend radially inward from each cusp supportand attach together at a common location. The common location may be onthe axis of the holder that coincides with the valve axis when theholder and valve are attached.

A connector may be provided extending along the holder axis to which thelegs join. The connector has a coupling for receiving a handle for theholder and a length suitable for manually grasping. In one embodiment,the connector is formed separately from the legs and joined thereto. Inaddition, the legs may be formed separately from the cusp supports andjoined thereto.

In an exemplary form, the cusp supports are multiple pieces joinedtogether, wherein each piece may include two halves of adjacent cuspsupports and a commis sure support. In the multiple piece embodiment,multiple legs may extend radially inward from each cusp support andattach together at a common location, wherein each piece has two leghalves extending radially inward from each of its cusp support halves,and wherein each pair of adjacent leg halves makes up one of the holderlegs.

The holder may further include a central hub with a plurality ofradially outward upper legs connected to the commis sure supports, and aplurality of lower legs angled downward and outward connected to thecusp supports. Each lower leg preferably has a width from the hub to aterminal end that is greatest at the terminal end to provide moresurface area to contact the corresponding valve cusp.

Another aspect of the invention is a combined flexible heart valve andholder. The combination includes a prosthetic flexible heart valvehaving multiple leaflets joined together at a periphery of the valve atvalve commissures that are generally axially aligned and evenly disposedabout a valve axis. The valve commissures are configured for radialmovement with respect to the valve axis and are each disposed betweenadjacent curvilinear valve cusps along the periphery of the valve. Thevalve leaflets coapt along the valve axis and curve in a direction toform an inflow side and an outflow side of the valve. The combinationincludes a holder attached to the outflow side of the valve having cuspsupports that contact and axially support the valve cusps. The holderalso has commissure supports between each two of the cusp supports thataxially support the valve commissures yet permit radial their radialmovement with respect to the valve axis.

The holder preferably includes structure for substantially preventingtorsional deformation of the flexible heart valve during implantation.The holder further may include a valve contacting portion having agenerally continuous curvilinear structure conforming to the peripheryof the valve and defining the alternating cusp and commissure supports.A central hub with a plurality of legs angled downward and outward maybe connected to the cusp supports. In one version, the valve contactingportion is integrally formed separate from the legs, while in anotherthe valve contacting portion is formed of a plurality of separatepieces, each piece defining at least a part of one of the legs. Eachseparate piece may define a half of two adjacent cusp supports, and maybe formed of a wire.

The combination further may include commissure attachment suturesconnecting the commissure supports to the valve commissures. Theflexible heart valve may include a sewing band that generally conformsto the valve cusps and commissures, wherein the commissure attachmentsutures connect the commissure supports to the sewing band at the valvecommissures. The holder further may include a valve contacting portionhaving a generally continuous curvilinear structure conforming to theperiphery of the valve and defining the alternating cusp and commissuresupports, wherein the commissure attachment sutures are severable at thecommissure supports and wherein the commissure supports include leafletguard sections that structurally protect the valve leaflets from beingcut by a blade in severing the commissure attachment sutures.

The combination further may include cusp attachment sutures connectingthe cusp supports to the valve cusps. The flexible heart valve mayinclude a sewing band that generally conforms to the valve cusps andcommissures, wherein the cusp attachment sutures connect the cuspsupports to the sewing band at the valve cusps. Desirably the cuspattachment sutures are routed so as to cross a common cut point on theholder such that the plurality of attachments between the cusp supportsand valve cusps can be severed with one cut. The holder may furtherinclude a central hub with a plurality of legs angled downward andoutward connected to the cusp supports, wherein the cusp attachmentsutures each loop through the valve at the valve cusps with one segmentbeing tied to the cusp support and a second segment extending up thecorresponding leg to the hub, across the common cut point. A sleeve maysurround each leg within which the second segment is contained.

The holder may include two stages, a first stage having the cuspsupports and a second stage having the commissure supports, the twostages being formed so as to be separable. The first stage may include acentral hub and a plurality of legs angling outward and downward to formthe cusp supports at their terminal ends. The second stage may include aflexible band around which the commissure supports are spaced, the bandpermitting the commissure supports to flex radially with respect to oneanother.

In another aspect of the present invention, a holder is provided formounting the flexible heart valve. The holder includes a central hubwith a plurality of radially outward upper legs, and a plurality oflower legs angled downward and outward. The upper and lower legs areadapted to connect to the alternating cusps and commissures of aflexible valve so as to maintain the position of the valve duringimplantation.

The present invention further provides a combination of a flexibleprosthetic heart valve and a rigid holder. The flexible heart valveincludes alternating cusps and commissures in a generally cylindricalconfiguration adapted to move radially in and out with respect to oneanother. The holder includes structure for maintaining a relativelyfixed shape of the flexible prosthetic heart valve during implantation.

The present invention further provides a method of implantation of aheart valve, including the steps of: providing a flexible heart valvehaving alternating cusps and commissures in a generally cylindricalconfiguration and adapted to move radially in out with respect to oneanother; attaching a holder to the valve that restricts relative axialand torsional movement of the cusps and commissures; positioning theheart valve in proximity to an anatomical orifice; implanting the heartvalve; and, disconnecting the holder from heart valve. The holder mayinclude cusp supports that contact and axially support the valve cuspsand commissure supports between each two of the cusp supports thataxially support the valve commissures yet permit radial their radialmovement with respect to the valve axis. In the latter case, the methodmay include visualizing the site of valve implantation by flexing one ofthe valve commissures radially inward while being supported by thecorresponding commissure support of the holder.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a sectional view through the left half of a human heartshowing a systolic phase of left ventricular contraction;

FIG. 2 is a sectional view through the left half of a human heartshowing a diastolic phase of left ventricular expansion;

FIG. 3 is an exploded perspective view illustrating sub-assemblies of aprosthetic heart valve of the present invention;

FIG. 4A is a top plan view of an internal stent of the prosthetic heartvalve of the present invention;

FIG. 4B is an elevational view of the internal stent of FIG. 4A;

FIG. 5 is an elevational view of a stent assembly of the prostheticheart valve;

FIGS. 6A and 6B are sectional views through two locations of the stentassembly, taken along lines 6A-6A and 6B-6B of FIG. 5;

FIGS. 7A, 7B, and 7C are plan views of leaflets suitable for use in theprosthetic heart valve of the present invention;

FIG. 8 is an exploded perspective view of a stent/leaflet sub-assemblyand a connecting band of the prosthetic heart valve of the presentinvention;

FIG. 9 is an elevational view of an inner member of the connecting band;

FIG. 10 is a cross-sectional view through a cusp of the connecting bandshown in FIG. 8;

FIG. 11 is a perspective view of an assembled prosthetic heart valve ofthe present invention;

FIG. 12A is a cross-sectional view through a cusp region of theprosthetic heart valve of the present invention, taken along line12A-12A of FIG. 11, and showing a portion of the host annulus inphantom;

FIG. 12B is a cross-sectional view through a commissure region of theprosthetic heart valve of the present invention, taken along line12B-12B of FIG. 11, and showing a portion of the host aortic wall inphantom;

FIG. 13 is a schematic view showing relative movement of the aortic andannulus walls during systolic flow;

FIG. 14A is a plan view of only the stent members of the prostheticvalve flexed in accordance with the anatomical motions during systoleshown in FIG. 13;

FIG. 14B is an elevational view of the stent members flexed inaccordance with the anatomical motions during systole shown in FIG. 13;

FIG. 15 is a schematic view showing relative movement of the aortic andannulus walls during diastolic flow;

FIG. 16A is a plan view of only the stent members of the prostheticvalve flexed in accordance with the anatomical motions during diastoleshown in FIG. 15;

FIG. 16B is an elevational view of the stent members flexed inaccordance with the anatomical motions during diastole shown in FIG. 15;

FIG. 17 is a perspective view of an alternative stent assembly for usein a prosthetic heart valve in accordance with the present invention;

FIG. 18 is a perspective view of an internal stent of the stent assemblyof FIG. 17;

FIG. 19 is an exploded view of a commissure tip region of the stentassembly of FIG. 17;

FIGS. 20A-20E are elevational views of alternative stents for use in aprosthetic heart valve in accordance with the present invention;

FIG. 21 is a detailed view of a commissure region of the alternativestent of FIG. 20E;

FIG. 22 is a detailed view of a commissure region of a still furtheralternative stent accordance with the present invention;

FIG. 23 is an exploded perspective view of the prosthetic heart valve ofthe present invention and a holder used during implantation of thevalve;

FIG. 24 is a perspective view of the holder coupled to the valve;

FIG. 25 is a top plan view of the holder coupled to the valve;

FIG. 26 is a cross-sectional view through the holder and valve, takenalong line 26-26 of FIG. 25;

FIGS. 27A ad 27B are perspective views of an alternative holder for theprosthetic heart valve of the present invention used during implantationof the valve;

FIG. 28 is a perspective view of an exemplary holder attached to aflexible heart valve of the present invention having cusp and commissure supporting sections;

FIGS. 29A-29D are detail views of portions of the combined holder andheart valve of FIG. 28;

FIG. 30 is an assembled perspective view of the valve holder of FIG. 28;

FIG. 31 is an exploded perspective view of the valve holder of FIG. 28;

FIG. 32 is a perspective view of one piece of a valve contacting portionof the valve holder of FIG. 28;

FIG. 33 is a top plan view of a portion of the valve holder of FIG. 28attached to a flexible heart valve;

FIG. 34 is a perspective view of an alternative heart valve holder ofthe present invention having cusp and commissure supporting sections;

FIG. 35 is a perspective view of a still further alternative heart valveholder of the present invention having cusp and commissure supportingsections, and attachment points only at the valve commissures;

FIG. 36 is a detail view of a removable attachment of the holder of FIG.35 to a valve commissure;

FIG. 37 is a perspective view of a one-piece heart valve holder of thepresent invention having cusp and commissure supporting sections;

FIG. 38 is a perspective view of a two-piece heart valve holder of thepresent invention having cusp and commissure supporting sections;

FIG. 39 is a perspective view of an alternative one-piece heart valveholder of the present invention having cusp and commissure supportingsections and a series of suture attachment apertures;

FIG. 40 is a perspective view of an alternative one-piece heart valveholder of the present invention having cusp and commissure supportingsections and a handle connection joined to a single cusp supportingsection;

FIG. 41 is a perspective view of a two-stage heart valve holder of thepresent invention attached to a flexible heart valve;

FIG. 42 is an exploded perspective view of the two-stage heart valveholder of FIG. 41;

FIG. 43 is a perspective view showing the two-stage heart valve holderof FIG. 41 exploded from the flexible heart valve; and

FIG. 44 is a perspective view showing the two-stage heart valve holderof FIG. 41 exploded into its two parts with a flexible stage remainingattached to the flexible heart valve.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention provides a highly flexible aortic heart valve thatis attached generally along a scalloped or undulating perimeterdownstream from where the natural leaflets were originally attached. Thenatural leaflets include arcuate cusp portions separated by commoncommissure portions. If the natural valve has three leaflets, and has avertically oriented flow axis, the leaflets are evenly distributedcircumferentially 120° apart with lower cusp portions and upstandingcommissure portions. The commissure portions are connected between thecusp portions and are generally axially aligned along the aortic wall.The annular root of an aortic valve is composed of fibrous tissue andgenerally conforms to the undulating perimeter of the valve to supportthe leaflets. In this respect, implanting the aortic heart valve of thepresent invention involves excising the natural leaflets and attachingthe prosthetic heart valve proximate the fibrous annulus, but also inpart up the aortic wall. Because of the particular construction of thepresent heart valve, as will be described below, the attachment means,be it sutures, staples, adhesives, or otherwise, may be anchored intothe aortic wall itself, adjacent to the fibrous annulus.

Anatomy

To better illustrate the advantages of the flexible heart valve of thepresent invention, an understanding of the movement of the annulus andaorta is helpful. In this regard, FIGS. 1 and 2 illustrate the twophases of left ventricular function; systole and diastole. Systolerefers to the pumping phase of the left ventricle, while diastole refersto the resting or filling phase. FIGS. 1 and 2 illustrate in crosssection the left chamber of the heart with the left ventricle 20 at thebottom, and the ascending aorta 22 and left atrium 24 diverging upwardfrom the ventricle to the left and right, respectively.

FIG. 1 illustrates systole with the left ventricle 20 contracting, whileFIG. 2 illustrates diastole with the left ventricle dilating. The aorticvalve 28 is schematically illustrated here as having leaflets 30.Contraction of the ventricle 20 causes the mitral valve 26 to close andthe aortic valve 28 to open, and ejects blood through the ascendingaorta 22 to the body's circulatory system, as indicated in FIG. 1 by thearrows 32. Dilation of the ventricle 20 causes the aortic valves 28 toclose and mitral valve 26 to open, and draws blood into the ventriclefrom the left atrium 24, as indicated in FIG. 2 by the arrows 33.

The walls of the left chamber of the heart around the aortic valve canbe generally termed the annulus region 34 and the sinus region 36. Theannulus region 34 generally defines an orifice that is the narrowestportion between the ventricle 20 and ascending aorta 22, which as notedabove is composed of generally fibrous tissue. The sinus region 36 isthat area just downstream from the annulus region 34 and includessomewhat elastic, less fibrous tissue. Specifically, the sinus region 36typically includes three identifiable, generally concave sinuses(formally known as Sinuses of Valsalva) in the aortic wall intermediatethe upstanding commissures of the valve 28. The sinuses are relativelyelastic and are constrained by the intermediate, more fibrous commissures of the aortic annulus. Those of skill in the art will understandthat the annulus region 34 and sinus region 36 are not discretelyseparated into either fibrous or elastic tissue, as the fibrouscommissures of the annulus extend into the sinus region 36.

The sinuses tend to move in and out to facilitate fluid dynamics of theblood in conjunction with systole and diastole. During systole, as seenin FIG. 1, the sinus region 36 expands somewhat to a diameter A. Thisfacilitates blood flow through the ascending aorta 22 to the rest of thebody. In contrast, during the diastolic phase as seen in FIG. 2, thesinus region 36 contracts somewhat to a smaller diameter B. Thediameters A and B are intended to be a measurement of the radialmovement of the commis sure regions of the valve 28. In this regard itwill be understood that the cross-sections shown are not taken in asingle plane, but instead are taken along two planes angled apart 120°with respect one another and meeting at the midpoint of the aorta 22.The sinus region 36 has a neutral, or relaxed diameter (not shown)somewhere in between diameters A and B.

The annular region 34 also moves in and out during the systolic anddiastolic phases. As seen in FIG. 1, the annular region 34 contractssomewhat to a diameter C during systole. In contrast, during thediastolic phase as seen in FIG. 2, the annular region 34 expandssomewhat to a larger diameter D. Much like the sinus region 36, theannular region 34 has a neutral, or relaxed diameter (not shown)somewhere in between diameters C and D.

As will be explained more fully below, the prosthetic valve of thepresent invention accommodates the in and out movements of both theannular region 34 and the sinus region 36. That is, alternatingperipheral portions of the prosthetic valve are attached to the annularregion 34 and the sinus region 36 and move accordingly. It is importantto point out that the preceding discussion of dynamic movement of theannulus and sinus regions is based on preliminary understanding of suchmovement. That is, direct measurements of these movements areproblematic, and thus certain assumptions and predictions must be made.The actual dynamic movement in any particular human heart may bedifferent, but the principles of the present invention would stillapply. That is, relative movement in the annulus and sinus regionsduring systole and diastole does exist, and the flexible prostheticheart valve of the present invention can accommodate any such movement.

Valve Subassemblies

With reference now to FIG. 3, the primary sub-assemblies of a preferredembodiment of the prosthetic heart valve 40 of the present invention areshown in exploded view. For purposes of discussion, the directions upand down, upper and lower, or top and bottom, are used with reference toFIG. 3, but of course the valve can be oriented in any direction bothprior to and after implantation. From top to bottom, the heart valve 40comprises a group 41 of three leaflets 42, three angled alignmentbrackets 44, a stent assembly 46, and a connecting band 48. Each of thesub-assemblies seen in FIG. 3 is procured and assembled separately(except for the group of leaflets, as will be explained), and thenjoined with the other sub-assemblies to form the fully assembled valve40 as seen in FIG. 11.

The prosthetic valve 40 is a trifoliate valve with three leaflets 42.Although three leaflets are preferred, and mimic the natural aorticvalve, the principles of the present invention can be applied to theconstruction of a prosthetic valve with two or more leaflets, dependingon the need.

Each of the sub-assemblies seen in FIG. 3 include three cusps separatedby three commissures. The leaflets 42 each include an arcuate lower cuspedge 50 terminating in upstanding commissure regions 52. Each leaflet 42includes a coapting or free edge 54 opposite the cusp edge 50. In theassembled valve 40, the cusp edges 50 and commissure regions 52 aresecured around the periphery of the valve, with the free edges 54permitted to meet or “coapt” in the middle. The stent assembly 46 alsoincludes three cusps 60 separated by three upstanding commissures 62. Inlike manner, the connecting band 48 includes three cusp portions 64separated by three upstanding commissure portions 66. Each of thesub-assemblies will now be described in detail.

Stent Assembly

Various components of a preferred stent assembly 46 are seen in FIGS.4-6. The stent assembly 46 comprises an inner stent 70 and an outercloth cover 72. More specifically, the inner stent 70 desirably includesthree identical and separate stent members 74, each of which has aseparate cloth covering. As seen best in FIG. 4B, each stent member 74comprises an arcuate lower cusp region 76 and upstanding commissureregions 78 each terminating at a tip 80. The stent members 74 compriseelongate rods or wires, preferably made out of an elastic biocompatiblemetal and/or plastic alloy, such as Elgiloy®, Nitinol, polypropylene,etc. The material selected for stent members 74 should be elastic topermit flexing along their lengths, but should possess a relatively highmodulus of elasticity to avoid asymmetric deformation of the constructedvalve 40. The stent 70 supplies an inner frame for the valve 40 that isrelatively more rigid than the other components. Therefore, the stent 70acts to limit total flexibility of the valve 40.

Alternatively, the material for the stent 70 may be highly flexible soas to add relatively little reinforcement to the valve 40. For example,the stent members 74 may be formed of a length of medical grade siliconethat provides some physical structure around the valve that helps institching fabric around the valve, and also helps provide some bulk forgrasping and sewing the valve in place, but otherwise does not reducethe flexibility of the other components. In this case, the stent 70 isdesirably formed of a single piece (such as seen in FIG. 20D) and thecommissures are inherently flexible, enabling the cusp regions 76 toflex or pivot with respect to one another. This very high flexibility ofthe valve 40 minimizes any unwanted impediment to the natural annulusand aortic wall movement, and desirably maximizes the flow orificeformed though the valve, thus reducing any pressure loss therethrough.The highly flexible stent material may be provided in one or multiplefilaments, with or without a surrounding enclosing sleeve, and may besilicone as mentioned, polypropylene, Delrin, polyurethane,polytetrafluoroethylene (PTFE), or the like. An exemplary thickness ofthe highly flexible stent material is about 0.011-0.013 inches for amonofilament version, or up to 0.025 inches with multiple filaments.

The stent members 74 are desirably bent into the illustrated shape,using conventional wire-forming techniques. Each of the stent members 74is identical, and terminates in the tips 80 which are bent inward withrespect to the arcuate cusp regions 76 to nearly form closed circles. Asis seen in FIG. 4B, a gradual radially outward bend 82 (with respect tothe cylindrical stent 70) is provided in the stent members 74 at atransition between each of the commissure regions 78 and theintermediate cusp region 76. This bend 82 permits each of the stentmembers 74 to remain in a circular configuration, as seen from above inFIG. 4A. That is, if the cusp regions 76 extended in a plane betweeneach of the commissure regions 78, the plan view would be somewhattriangular. Instead, each of the cusp regions 76 includes a lower apex84, and the apices of all of the cusps define a circle concentric withand having the same diameter as a circle defined by all of the tips 80.The stent 70 thus defines a substantially cylindrical volumetherewithin. Of course, other volumes may be defined by the stent 70wherein the tips 80 define a circle that is smaller or larger than acircle defined by the apices 84. For example, the apices 84 may beprovided outward from the tips 80 so the stent 70 defines afrusto-conical volume therewithin.

As seen in FIG. 5, each of the stent members 74 is preferably coveredwith a generally tubular cloth 72 from tip to tip 80. The cloth cover 72is a biocompatible fabric, such as polyterephthalates, and has a varyingcross sectional shape, as indicated in FIGS. 6A and 6B. Morespecifically, the cloth cover 72 includes a tubular portion closelyconforming around each of the stent members 74 and a flap 86 extendingradially outward from the stent member (with respect to the curvature ofthe cusp regions 76). The cloth cover 72 is formed by wrapping anelongated sheet of fabric around each of the stent members 74 andjoining the free edges with sutures 88 to form the flaps 86. As seen inFIG. 5, the flap 86 extends from each stent member 74 in a directionthat is generally outward with respect to the cusp region 76, andcontinues in the same general orientation up the commissure regions 78to the tips 80. The flap 86 has a dimension that is longest at the apex84 of each cusp region 76 and shortest at the tips 80. Indeed, the flap86 is preferably nonexistent at the tips 80, and gradually increases insize from the tip 80 to the apex 84. Therefore, the cross-section ofFIG. 6A taken through the commissure region 78 shows the flap 86 havinga small dimension d1, and the cross-section of FIG. 6B taken through theapex 84 shows the flap 86 having a longer dimension d2.

The final component of the stent assembly 46 is an attachment means 90for joining each of a cloth-covered stent members 74. Preferably, theattachment means 90 comprises threads or sutures sewn through thecentral holes in each of the circular tips 80, as shown in FIG. 5,although other suitable attachment means could be used, such as rings,cinches, or the like. The attachment means 90 may be wrapped around orsewn through the cloth cover 72. In joining the tips 80, the attachmentmeans 90 are desirably not wrapped extremely tightly, but are insteadprovided with some slack to permit relative movement of the tips, aswill be described below. When the stent members 74 are attached, as seenin FIG. 5, the stent 70 exhibits three cusps corresponding to the cuspregion 76 of each member, and three upstanding commissures defined bythe juxtaposition of adjacent pairs of commis sure regions 78.

In a preferred embodiment of the present invention the attachment means90 comprises a non-bioresorbable material to ensure that the individualstent members 74 are maintained in the shape of the stent 70. In analternative configuration, however, the attachment means 90 comprises abioresorbable material that dissolves over a period of time afterimplantation. In such an embodiment, the natural host tissues may havegrown in and around the porous portions of the valve 40 to help retainthe original shape of the stent 70. In some instance, however, verylittle tissue overgrowth may have occurred prior to the attachment means90 dissolving, and the individual stent members 74 are permitted to moveradially a great deal with respect to one another. In the latterembodiment, wherein the stent members 74 are permitted to spread apart,the connecting band 48 may be re-configured to be non-continuous at thecommissure portions 66 (see FIG. 3). As a consequence, each individualstent member 74 and associated leaflet 72 moves entirely independentlyof the others, albeit all oscillating with the natural contractions andexpansions of the surrounding aortic wall. Such independent leafletmovement may greatly reduce any potential pressure drop across thevalve. Although one embodiment is to provide a bioresorbable attachmentmeans 90 such as the sutures shown in the embodiment of FIG. 5, those ofskill in the art will understand that any of the coupling meansconnecting the individual stent members 74 disclosed in the presentapplication could be modified to resorb over time.

The stent assembly 46 provides an inner support frame that is generallyrigid along any one of stent members 74, but which permits the stentmembers to move with respect to one another. In this context, “generallyrigid” refers to the structural strength of the stent members 74 that issufficient to maintain the general shape of the stent 70, but thatpermits some flexing along the length of the stent members. Though thestent members 74 are generally rigid, they are able to move with respectto one another. More particularly, joining the stent members 74 with theattachment means 90 creates nodes or pivot points of the valve 40 at thecommissures 62 of the stent assembly 46. As will be more fully explainedbelow with reference to FIGS. 13-16, the stent members 74 are permittedto pivot with respect to one another as they move radially inward andoutward. Inward pivoting is permitted by spaces 94, seen in FIG. 5,defined between adjacent cloth-covered commissure regions 78 of eachstent member 74. These regions 94 are generally triangular and graduallyincrease in size from the attached commis sure tips to the divergingcusps.

Leaflet Configurations

FIGS. 7A, 7B, and 7C are plan views of various configurations ofleaflets 42 suitable for use in the prosthetic heart valve 40. FIG. 7Ashows a leaflet 42 having the aforementioned cusp 50, commissure regions52, and free edge 54. It will be noted that the coapting edge 54comprises two linear portions extending from an apex 100 to outer tips102. The two portions of the free edge 54 are angled with respect to oneanother and define sides of a triangular region 104 having as itshypotenuse an imaginary line 106 extending between the opposed tips 102.The triangular region 104 of each leaflet 42 is under less tensionduring dynamic motion of the valve 40, and helps ensure coaptation ofthe leaflets. That is, the leaflets 42 are generally secured along thecusp 50 and commissure regions 52, and thus the majority of each leaflet42 is placed in stress except in the region above imaginary line 106. Inthis regard, an imaginary (dashed) fold line 108 defines an outer margin110 of the leaflet 42 that is used to secure the leaflets into the valve40. As will be clear from the discussion below, the margins 110 aresutured between the stent assembly 46 and connecting band 48 (FIG. 3),and the free edge 54 of the leaflet extends across the cylindricalregion defined within the valve 40, and is generally free to move inthat region. Because the triangular leaflet region 104 is relativelystress-free, it tends to roll over under the influence of fluid dynamicforces, thus helping the three leaflets to coapt and prevent valveinsufficiency.

FIG. 7B shows a leaflet 112 that is substantially the same as theleaflet 42 of FIG. 7A, and thus like elements will be given the samenumbers. The leaflet 112 includes a pair of generally triangular shapedcommissure tabs 114 in the commissure regions 52. The tips 102 are thusspaced farther apart than in the version shown in FIG. 7A. Thecommissure tabs 114 are used to more securely fasten each of theleaflets to the commissures 62 of the stent assembly 46 (FIG. 3). Thecloth cover 72 of the stent assembly 46 includes a flap 86 (FIG. 5)which diminishes in size in the commissure regions. The tabs 114 arethus wrapped farther around the cloth-covered stent assembly 46 in thecommissure regions and sutured thereto, thus facilitating a more durableconnection.

FIG. 7C is a further variation of a leaflet 116 which is, again, thesame in all respects to the leaflets described above, except forsomewhat trapezoidal-shaped commissure tabs 118. Again, the commissuretabs 118 help to secure the leaflets 116 in the prosthetic valve 40.

Stent/Leaflet Sub-Assembly

FIG. 8 illustrates a stent/leaflet sub-assembly 120 in which theleaflets 42 are secured to the stent assembly 46. Preferably, leaflets42 are pre-attached to align the free edges 54. In this manner, the freeedges 54 of each two adjacent leaflets 42 extend outward injuxtaposition and are received within the triangular space 94 definedbetween the commissure regions 78 of the stent assembly 46 (FIG. 5). Thegroup of leaflets 41 is thus “inserted” underneath the stent assembly 46until the juxtaposed free edges 54 of the leaflets 42 are in closeproximity below the attachment means 90. The outer margin 110 of eachleaflet 42 is folded underneath the corresponding cusp 60 of the stentassembly 46. At this point, sutures or other such means attach themargins 110 to the flap 86 of the stent assembly 46. The leaflets 42 canremain attached to one another at their adjacent tips 102 (or along thefree edges 54 near the tips), or can be separated for maximum valveflexibility or when the stent is designed to separate into individualstent members by bio-resorption of a commissure couple.

If either the leaflet 112 or leaflet 116 of FIG. 7B or 7C are used, therespective commissure tabs 114 or 118 are wrapped around the adjacentpart of the stent assembly 46 and secured thereto. In a preferredassembly method, the leaflets 42 are simply retained in position withrespect to the stent assembly 46 with temporary sutures or other suchmeans, to permit the stent/leaflet subassembly 120 to be finally joinedtogether with the connecting band 48 of FIG. 8.

FIG. 8 also illustrates the three alignment brackets 44 and that eachhas a generally L-shaped cross-section and comprises a cloth-coveredinner member (not separately numbered). The inner member preferably hasminimum elasticity, but is relatively thin and lightweight. Onepreferred material for the inner member is a polyester film such asMylar®. The brackets 44 are preferably joined to the valve 40 at thetime the stent/leaflet sub-assembly 120 and connecting band 48 arejoined, and thus will be described more fully below with respect to FIG.11.

Connecting Band

FIGS. 9 and 10 illustrate the connecting band 48 in more detail,comprising an inner member 130 surrounded by a cloth cover 132. Asmentioned previously with respect to FIG. 3, the connecting band 48includes three cusp portions 64 alternating with commissure portions 66,all generally formed in a tubular configuration. This shape is providedby the inner member 130, with the cloth cover 132 simply draped and sewnthereover. In a preferred embodiment, the inner member 130 is molded ofsilicone rubber, and the cloth cover 132 is polyterephthalate.

The inner member 130 has a varying cross sectional shape along the cuspsand commissures. FIG. 10 is cross-section through one of the cuspportions 64 of the connecting band 48, and shows a region of the innermember 130 having an inner ledge 134 and upwardly angled outer freemargin 136. The cloth-covered ledges 134 extend generally radially anddefine three stent support regions 138 of the connecting band 48, asseen in FIG. 8. The ledge 134 has its greatest radial dimension at themidpoint of each of the cusp portions 64 and gradually tapers down insize toward the commissure portions 66. Likewise, the free margins 136form their greatest outward angle with respect to a central axis of theconnecting band 48 at each cusp portion 64, and gradually re-align to beparallel to the central axis in the commissure portions 66. Thecross-section of the inner member 130 at the commissure portions 66 isseen in FIG. 12B. A series of triangular shaped ribs 140 projectsoutward from the inner member 130. The ribs 140 are formed around theentire inner member 130, along both the cusp and commissure regions. Asseen in FIG. 8, the commis sure portions 66 of the connecting band 48define generally axial gaps 142 that help permit flexing of the valve40. It should be noted that the connecting band 48 may be discontinuousat the commissure portions 66 if the valve has bioresorbable commissuresand is designed to separate into individual “leaflets.”

Assembled Valve

FIG. 11 illustrates the assembled valve 40 in perspective, while FIGS.12A and 12B show cross-sections through a valve cusp 150 and valvecommissure 152, respectively. The connecting band 48 is sewn orotherwise attached to the exterior of the stent/leaflet subassembly 120.Actually, as seen in FIG. 12A, the connecting band 48 is attachedunderneath the stent/leaflet subassembly 120 in the cusp 150, but thefree margins 136 of the connecting band are positioned to the outside ofthe subassembly. In addition, the alignment brackets 44 are installedwith a vertical leg 156 interposed between the commissures 62 of thestent assembly 46 and the commissure portions 66 (FIG. 3) of theconnecting band 48. A horizontal leg 154 of each of the alignmentbrackets 44 projects radially inward to cover the tips 80 of the stentassembly 46. The alignment brackets 44 help hold each two adjacent tips80 of the three-piece stent 70 together, especially helping to preventradial mis-alignment. The brackets also provide flat surfaces which aholder can contact, as seen best in FIG. 26.

With reference to the cross-section of FIG. 12A, the sandwichedconfiguration of the stent assembly 46, leaflet 42, and connecting band48 can be seen. More specifically, the cloth flap 86 of the stentassembly 46 aligns with the leaflet margins 110, which in turn rest onthe stent supports 138. A series of suture stitches 158 are used tosecure these elements together. Preferably, the flap 86 terminates atthe same location as the margin 110 of each leaflet 42, and at thecorner defined in the connecting band 48 between each ledge 134 and freemargin 136. The radially innermost wall of the ledge 134 is preferablyinward from the stent member 74. This construction helps prevent thestent 70 from migrating downward with respect to the connecting band 48.

The host annulus 162 is seen in phantom with the aortic wall 164continuing upward therefrom. It can be readily seen that the angledshape of the cusp portions 64 of the connecting band 48 conform nicelyto the host annulus region. The triangular ribs 140 provide volume atthe free margins 136 of the connecting band 48 to facilitate connectionto the natural tissue; in other words, more volume provides more of a“bite” for the surgeon to secure the band 48 with a suture needle.Although the conventional means for attaching the valve 40 to the hosttissue is with sutures, which are not shown, the present inventionshould not be construed as limited to being implanted with sutures andother means such as staples, adhesives, and the like could be used.

Now with reference to FIG. 12B, the assembly of the valve components inthe commissure region is seen. The commissure edges 52 of each of theleaflets 42 are sandwiched in between the stent assembly 46 andconnecting band 48. More particularly, the commissure edges 52 aresandwiched between the flaps 86 and the generally planar commissureportions 66 of the connecting band 48 (FIG. 8). Sutures 170 are providedto join these elements together. Again, the commissure edges 52preferably terminate at the same location as the flaps 86. FIG. 12B alsoillustrates the gap 142 provided in the commissure regions of theconnecting band 48, and the lack of structural connection between thetwo sides of each valve commis sure 152.

FIG. 12B shows in phantom a portion of the aortic wall 172 to which thecommissures 152 of the valve 40 are attached. Again, the particularattachment means is not shown, but the connecting band 48 istraditionally sutured to the wall 172.

Dynamic Motion of the Prosthetic Heart Valve

FIGS. 13 and 15 illustrate a conduit portion of a heart in the region ofthe aortic valve and relative motions of the conduit walls duringsystole and diastole, respectively. In particular, FIG. 13 shows an openvalve 200 and systolic blood flow 202, while FIG. 15 shows a closedvalve 204 and diastolic back flow of blood 206. As described withrespect to FIGS. 1 and 2, the regions around the aortic valve can begenerally separated into an annulus region 208 and a sinus region 210.

As mentioned previously, the annulus region 208 is expected to contractduring the systolic phase, as indicated by the arrows 212 in FIG. 13,and expand during the diastolic phase, as indicated by the arrows 214 inFIG. 15. Conversely, the sinus region 210 is expected to expand duringthe systolic phase, as indicated by the arrows 216 in FIG. 13, and isexpected to contract during the diastolic phase, as indicated by thearrows 218 in FIG. 15. The movements of the conduit walls are shown withrespect to a neutral or relaxed position 220, and may be exaggeratedfrom the true movements. Also, as mentioned above, these movements areeducated guesses and may be different for some, if not most patients.However, the flexible heart valve of the present invention accommodatesall variations of such movements.

FIGS. 14 and 16 schematically illustrate the synchronous movement of theprosthetic valve 40 of the present invention with respect to themovements of the host tissue in systolic and diastolic phases as seen inFIGS. 13 and 15. To simplify this explanation, FIGS. 14 and 16 onlyillustrate the stent 70 of the present invention, which as previouslydescribed acts as a limitation to movement of the entire valve 40 andfairly represents movement of the entire valve.

With reference to FIGS. 14A and 14B, during systole the valveexperiences outward commissure movement, as indicated by the arrows 230.At the same time, the valve experiences inward movement at the cusps, asindicated by the arrows 232. During diastole, in contrast, and as seenin FIGS. 16A and 16B, the valve experiences inward commissure movement,as indicated by the arrows 234. At the same time, the valve experiencesoutward movement at the cusps, as indicated by the arrows 236.

Alternative Stents

FIGS. 17-19 illustrate an alternative stent assembly 250 comprising aninner stent 252 and an outer cloth cover 254. As with the earlier stentassembly 46, the stent assembly 250 includes alternating cusps 256 andcommissures 258. As best seen in FIG. 18, the stent 252 includes threeseparate stent members 260 having arcuate commissure tips 262 that arecurved toward one another. A generally disk-shaped commissure housing264 encompasses the adjacent commissure tips 262, retaining the stentmembers 260 together while permitting relative pivoting.

FIG. 19 illustrates two adjacent commissure tips 262 and the commissurehousing 264 exploded into a male housing portion 266 and a femalehousing portion 268. The housing portions are so named because they arejoined together through interference between a button 270 of the malehousing portion 266 and an aperture 272 on the female housing portion268. Each portion of the commissure housing 264 includes a circulargroove 274 for receiving the arcuate tips 262. The grooves 274 combinedto form a circular channel having an axis 276 within which the arcuatetips 262 are received and can slide. When assembled together, thecommissure housings 264 thus provide nodes of rotation for each of thestent members 260.

FIG. 20A illustrates an alternative stent 280 suitable for use in aheart valve of the present invention. The stent 280 includes three stentmembers 282, each having commissures with a flex region 284 and tips286. The tips 286 of adjacent stent members 282 are secured together bysutures or other suitable means (not shown). The flex regions 284comprise sections of each stent member 282 which are bent away from eachother. The stent members 282 can thus pivot with respect to one anotherabout the connected tips 286. Upon inward movement of the stent members282, a fulcrum 288 is created by interaction between the stent membersat the lower end of the flex region 284. The relative flexibility ininward or outward movement of the stent members 282 can be modified byselection of the cross sectional size and shape of the stent members,and overall configuration of the flex region 284.

FIG. 20B illustrates a second alternative stent 290 suitable for use ina heart valve of the present invention. The stent 290 includes threewires 292 and has commissure regions 294 formed by bent ends of thewires and a junction member 296. In this embodiment, the junction member296 either rigidly holds the terminal ends of each of the wires 292, orpermits the wires to slide or otherwise flex with respect to oneanother. If the wires are rigidly attached to the junction member 296the shape of the wires in the commissure region 294 reduces stressrisers in bending.

FIG. 20C illustrates a third alternative stent 300 suitable for use in aheart valve of the present invention. The stent 300 comprising threeseparate wires 302 terminating at circular commissure tips 304. Each ofthe commissure tips 304 is rotatably fastened around a pin 306 providedon a junction plate 308 common to adjacent wires 302. In this manner,the tips 304 remained located close to one another, while the cusps ofthe wires 302 can pivot in and out.

FIG. 20D illustrates a fourth alternative stent 310 suitable for use ina heart valve of the present invention. The stent 310 is made in onepiece with a series of alternating cusps 312 and commissures 314. Thecommissures 314 comprising a nearly 360° bend in the stent 310 whichpermits each cusp 312 to easily flex with respect to the other cusps.

FIG. 20E illustrates a fifth alternative stent 320 suitable for use in aheart valve of the present invention. The stent 320 comprises threewire-like stent members 322, adjacent ones of which are joined togetherat commis sure regions 324 by a U-shaped coupling 326 and a pairflexible sleeves 328. FIG. 21 is a detail of one of the commis sureregions 324 showing in hidden lines the adjacent ends of the coupling326 and stent members 322. The couplings 326 are preferably sized withthe same diameter as the stent members 322, and the sleeves 328 aretubular with a constant diameter lumen. The sleeves 328 may be made ofsilicone, or a flexible polymer such as polyurethane or the like. Otherflexible interfaces such as sleeves 328 are contemplated, such as, forexample, a single block of silicone into which the commissure regions324 of the stent members 322 are molded.

FIG. 22 is a detailed view of a commissure region 330 of a still furtheralternative stent suitable for use in a heart valve of the presentinvention. The stent is made in one piece with adjacent cusps 332 beingjoined by a coil spring tip 334. Again, great flexibility is provided bythe coil spring tips 334 to enable relative motion of the cusps 332. Theamount of flexibility is selected as in any spring by varying thematerial, cross-sectional size and shape, and number of turns of thespring.

Valve Holder

FIGS. 23-26 illustrate a preferred holder 350 useful for implanting theflexible heart valve 40 of the present invention. As the heart valve 40is relatively flexible, the holder 350 must provide adequate support toinsure a stable platform for the surgeon to position the valve forattachment to the natural tissue. In other words, because the flexibleprosthetic heart valve 40 of the present invention exhibits alternatingcusps and commissures in a generally cylindrical configuration that areadapted to move radially in and out with respect to one another, theholder 350 desirably provides rigid structure for maintaining a fixedshape of the valve during implantation. In addition, the holder 350 mustinclude structure to allow quick release from the valve 48 after thevalve is implanted.

As seen in FIG. 23, the holder 350 comprises a proximal handle socket352 having an inner bore 354 for receiving the distal end of a handle(not shown). The socket 352 may be provided with internal threads, orother such quick-release coupling structure to facilitate handleconnection and disconnection. The holder 350 has three radiallyoutwardly-directed commissure legs 356, and three outwardly anddownwardly angled cusp legs 358. Consistent with the distribution of thecusps 150 and commissures 152 of the valve 40, the commis sure legs 356are oriented 120° apart, and the cusp legs 358 are oriented 120° apart,with the three commissure legs being offset with respect to the threecusp legs by 60°.

As seen in FIG. 24, each of the commissure legs 356 extends outward fromthe handle socket 352 into proximity with one of the valve commissures152 and is secured thereto with an upper suture 360. Likewise, each ofthe cusp legs 358 extends outward and downward from the handle socket352 into proximity with a midpoint of one of the valve cusps 150, and issecured thereto with a lower suture 362. The lower end of each cusp leg358 includes a concavity for mating with the corresponding rod-likestent member 74, as seen in FIG. 26. In this manner, each of the cusps150 and commissures 152 of the valve 40 is securely held in relation tothe others, thus facilitating implantation by the surgeon.

Details of the commissure legs 356 will now being described withreference to FIGS. 23 and 26. Each commissure leg 356 extends outwardfrom the handle socket 352 in a generally rectangular cross-sectioninterrupted by an upwardly-facing inner notch 370 oriented cross-wise tothe leg. And upwardly-facing radial channel 372 having a depth ofapproximately half of each commissure leg 356 extends from about theinner notch 370 to the outermost end of the leg. The inner notch 370 isnot quite as deep as the channel 372, as seen in FIG. 26. The radialchannel 372 divides the upper portion of each commissure leg 356 intotwo walls 374 a, 374 b. An eyehole 376 is formed in one of the walls 374a, and a corresponding outer notch 378 is formed in the other wall 374 baligned with the eyehole. The outer notch 378 is also not quite as deepas the channel 372.

With reference to FIGS. 24 and 26, the upper suture 360 is preferablytied to the eyehole 376 in the first wall 374 a. The suture 360 thenpasses across the channel 372, through the outer notch 378, and ispassed along the inner notch 370, again traversing the channel 372. Thesuture 368 is then passed through a suture-permeable portion of thevalve commissure 152, such as through the connecting band 48. Afterpassing through the commissure 152, the suture 360 is again loopedthrough one or both of the notches 370, 378 and re-tied to the eyehole376. By proper threading of the upper suture 360, each commissure 152can be secured to the commissure leg 356 and easily released byinserting a scalpel blade into the radial channel 372 to sever theportions of the suture therein.

Details of each cusp leg 358 can be seen in FIGS. 23 and 26. A pair oflongitudinal rails 380 a, 380 b are provided on the outer side of eachcusp leg 358. Toward the lower end of the rails 380 a,b, a pair ofaligned eyeholes 382 provide anchoring locations for the lower suture362. A scalpel guide or relief 384 is formed in one of the rails 380 b.As seen in FIG. 24, the lower suture 362 extends downward from theeyeholes 382, passes through a suture-permeable portion of the cusp 150,and is then returned and secured to the eyeholes 382. The relief 384exposes a portion of the lower suture 362 for severing by the surgeonusing a scalpel blade. It will thus be understood that the holder 350can be quickly released from the valve 40 by a series of six scalpelstrokes, with each of the sutures 360, 362 remaining attached to theholder 350 and being withdrawn from the valve 40 as the holder iswithdrawn.

FIGS. 27A and 27B illustrate an alternative holder 390 useful forimplanting the flexible heart valve 40 of the present invention. Theholder 390 is substantially similar to the holder 350 described above,but the ends of each of a plurality of rigid legs for attaching to thevalve cusps are flared, or, more precisely, each lower leg has a widthfrom a hub to a terminal end that is greatest at the terminal end toprovide more surface area to contact the corresponding valve cusp. Thatis, the holder 390 includes a plurality of upper legs 392 having agenerally constant width, and a plurality of lower legs 394 havingflared ends 396, the legs extending from a central hub 398. Again, theupper legs 392 extend radially outward to connect to the valvecommissures 152, and the lower legs 394 angle radially outward anddownward to connect to the valve cusps 150. The flared ends 396 impartgreater stability to the flexible valve 40 during implantation,especially helping to prevent movement of the cusps 150. In addition,the legs 194 remain fairly narrow until the flared ends 396 to maintaingood visibility through the spaces between the plurality of legs. Thatis, for example, the surgeon can continue to view the valve leaflets 42between the legs as a check on valve orientation.

FIG. 28 illustrates a further holder 420 of the present inventionattached to a flexible heart valve 422. (It should be noted that inFIGS. 28-33, the valve 422 is only schematically shown so as to betterillustrate the holder 420 structure.) As before, the valve 422 includesmultiple leaflets 424 joined together at adjacent juxtaposed valvecommissures 426 that are generally axially aligned and commonly disposedabout a valve axis (not illustrated) and are each disposed betweenadjacent curvilinear valve cusps 428. The holder 420 is shown withoutthe valve 422, assembled in FIG. 30 and exploded in FIG. 31.

As described and shown above in previous embodiments, the holder 420attaches to and securely maintains each of the cusps 428 and commissures426 of the flexible valve 422 in relation to the others, thusfacilitating implantation by the surgeon. In this regard, the holder 420may be relatively rigid to support and define the valve shape againstinadvertent external forces during the implant process. Optionally, theholder 420 may be somewhat flexible and resilient so to enabledeliberate manipulation by the surgeon desiring to view a portion of theheart anatomy occluded by the valve 422. For example, one of thecommissures 426 or cusps 428 may be radially bent inward along with theadjacent portion of the holder 420 so as to view the underlying annulus.Various flexible constructs of the holder 420 are contemplated, whichwill be further described below.

For orientation purpose, the coordinate axes of the holder 420 andattached valve 422 are: the axial direction or axis generally along theflow path through the valve and coincident with a central handle for theholder; the radial direction with respect to the axis; and thecircumferential or tangential direction also with respect to the axis.Most tissue heart valves include three commissures 426 and three cusps428 that mimic the natural valve peripheral shape. The three commissures426 are generally evenly circumferentially disposed about the flow axis(i.e., 120° apart), with the three cusps 428 being circumferentiallydisposed midway between each two commissure. The holder 420 of thepresent invention desirably maintains the axial and circumferentialorientation of the valve, while permitting some radial flexure. The needfor such flexure depends on the implantation technique used, and will bedescribed below.

With reference to FIGS. 28-31, and in particular FIG. 30, an exemplaryholder 420 includes a valve contacting portion 430 and a handleconnector 432. The valve contacting portion 430 includes a plurality ofcusp supports 434 arranged to contact the heart valve 422 generallyalong the valve cusps 428, and a plurality of commis sure supports 436connected to the cusp supports and arranged to abut the valvecommissures 426. In a preferred embodiment, the commissure supports 436are radially flexible enabling the valve commissures 426 to be flexedinward while in contact therewith; for example, the commissure supports436 may be made of a resilient, biocompatible material such as Nitinol.

The cusp supports 434 are formed in the same curve and dimensions as theassociated flexible heart valve 420, as seen in FIG. 28. The valve 420shown includes an outer sewing band 440 and the cusp supports 434 areshaped to abut and contact, or at least closely conform to, the innersurface of this band when the holder is positioned on the outflow sideof the leaflets 424. Through attachment structure to be described below,the cusp supports 434 and outer sewing band 440 at the valve cusps 428are coupled so as to reinforce the flexible valve 422 at thoselocations. It should be understood that other flexible heart valves thanthe version illustrated may be delivered using the exemplary holder 420,or other holders illustrated herein, and that the cusp supports 434 mayattach to structure other than the sewing band 440, such as to acloth-covered frame or stent structure.

As illustrated best in FIGS. 30 and 31, a plurality of wire-likeelements define the valve contacting portion 430 of the exemplary holder420, desirably forming a plurality (preferably three) of alternating andcontiguous curvilinear cusp supports 434 and commis sure supports 436.There is no discrete transition between the alternating supports 434,436, the curvilinear cusp supports eventually straightening and becomingoriented generally axially at intermediate sections 442 prior to thecommissure supports.

The contiguous cusp supports 434 and commissure supports 436 join to thehandle connector 432 via a plurality of legs 444. The legs 444 emanateradially outward from the centrally located distal end of the handleconnector 432 to several locations on the valve contacting portion 430.For example, as shown in FIG. 30, three legs 444 may extend between thehandle connector 432 and a mid-point of each cusp support 434, althoughthe legs may also extend to the commis sure supports 436 or both. Thecommon connection of the three legs 444 at the distal end of the handleconnector 432 enables positioning of the holder 420 (and attached valve422) to be controlled by manipulation of the handle connector.

FIGS. 31 and 32 best illustrate the exemplary wire-like valve contactingportion 430 and associated legs 444 formed in three pieces 450 a, 450 b,450 c. With specific reference to FIG. 32, each one of the three pieces450 comprises two halves 452 a, 452 b of adjacent cusp supports 434 anda commissure support 436. Each of the three pieces 450 also has two leghalves 454 a, 454 b extending radially inward from a respective cuspsupport half 452 a or 452 b. When the three pieces 450 a, 450 b, 450 care positioned evenly about an axis, each pair of adjacent leg halves454 makes up one of the holder legs 444 and two adjacent cusp supporthalves 452 a, 452 b in different holder pieces define a whole cuspsupport 434. Each leg half 454 terminates at a free end 456 that extendsgenerally axially and can be easily joined along with the othersimilarly aligned free ends to the handle connector 432. Preferably,each of the three pieces 450 is identical and the free ends 456 coincidegenerally along a central axis, so that the handle connector 432 liesalong the central axis as well. Each commissure support 436 includes aleaflet guard section 460 that is bent radially inward from the adjacentintermediate sections 442. The function of the leaflet guard sections460 will be described below with respect to the structure used to attachthe holder 420 to the valve 422.

FIG. 31 illustrates the handle connector 432 having a proximal stem 470and handle coupling 472 exploded from a distal hub member 473.Alternatively, of course, the entire handle connector 432 may be onepiece, and formed by molding, for example. The coupling 472 includesstructure such as an internally threaded socket for receiving a valvedelivery handle (not shown). The stem 470 has a length suitable toenable a surgeon to manually grasp it and manipulate the holder 420 andattached valve 422. Desirably, the length of the handle connector 432 isat least one inch, and preferably between one and four inches. Thehandle connector 432 is made of a material that is capable of beingstored in a solution in which the valve 422 is stored betweenmanufacture and usage. For example, typical bioprosthetic valves may bestored for periods of years in glutaraldehyde, and the handle connector432 may be made of a polymer that can withstand such storage conditions,such as Delrin. The distal hub member 473 may be internally threaded formating with external threads on the stem 470, wherein mutual cooperationof the two elements may serve to clamp the free ends 456 of the holderpieces together, such as having a bifurcated distal end 474 of the stemthat constricts upon mating with the hub member. Of course, numerousother ways to secure the free ends 456 to the handle connector 432 arepossible, including molding as a homogeneous structure.

FIGS. 28 and 29A-29D illustrate an exemplary system for removablysecuring the holder 420 to the valve 422 using sutures. In oneembodiment, at least the commis sure supports 436 are secured to thevalve commissures 426 in a manner that permits easy release, butpreferably both the commissure supports and cusp supports 434 are soconnected. Sutures are preferred as the means for attaching variouspoints on the holder 420 with coincidental points on the valve 422because of their flexibility, strength and severability. Of course,other means of attachment are contemplated, such as hooks, springclamps, and the like. The holder 420 and valve 422 may be attached atrelatively separated discrete points, as shown, or may be attached atmultiple points along their mating surfaces to result in a morecontinuous coupling.

With reference to FIGS. 28, 29A, 29B and 33, an exemplary arrangementfor joining each of the cusp supports 434 to the valve 422 with suturesis shown. Each cusp support 434 joins to the valve 422 with two lengthsof suture material 480 a, 480 b that are secured to the handle connector432 and extend in parallel segments down each of the legs 444. Thelengths of suture material 480 a, 480 b couple to the handle connector432 in a visible or otherwise accessible manner to enable severing by aknife blade. More specifically, and as seen in FIGS. 28 and 29A, thelengths of suture material 480 a, 480 b extending along each leg 444 aregathered at the lower end of the handle connector 432 and passed throughan eye hole 475 provided in a flange 476 projecting outward from thedistal hub member 473. The six strands of sutures then tie to a throughhole 477 or other such feature in the proximal stem 470. In this manner,common segments 478 of all six sutures 480 are exposed on the exteriorof the handle connector 432 to facilitate severing, or in other wordsthe sutures 480 are routed so as to cross a common cut point on theholder 420.

As seen in FIG. 29B, each length of suture material 480 a, 480 b travelsdown the respective leg 444 and passes through a portion of the sewingband 440 at a loop 481. From the loops 481, each length of suturematerial 480 a, 480 b turns radially inward and fastens by tying atknots 482, for example, to one of the pieces 450 a, 450 b of the valvecontacting portion 430. Anti-migration sleeves 483 (such as shrink-fitsleeves) prevent the knots 482 from sliding along the pieces 450 a, 450b. As mentioned above, the suture may also be secured to a differentpart of the valve 422 than the sewing band 440, as long as it may easilybe removed by pulling on its loose ends. The loop 481 is so formed andthe sewing band 440 is constructed to permit the suture to slide fromwithin the band by pulling one loose end.

FIG. 29D shows the cross-section through one of the exemplary holderlegs 444, and in particular the two lengths of suture material 480 a,480 b within a shaped sleeve 484 that conforms around the two juxtaposedleg halves 454 a, 454 b. The sleeve 484 may be formed of a polymer tubethat is shrink fit around the two leg halves 454 a, 454 b. A cylindricalforming mandrel (not shown) is desirably placed in a triangular arrayalong with the juxtaposed leg halves 454 a, 454 b, with the sleeve 484circumscribing all three rods. After shrinking, the sleeve 484 conformsclosely around the three rods and the mandrel is then removed, leavingthe hollow space as shown for easy assembly and sliding passage of thetwo lengths of suture material 480 a, 480 b.

Now with reference to FIGS. 28, 29C and 33, two lengths of suturematerial 490 a, 490 b each extends from a first anchor or knot 491secured to a midpoint of the leaflet guard section 460, via a loop 492that passes through the sewing band 440, to a second anchor or knot 493also on the leaflet guard section. In the embodiment shown, wherein theleaflet guard section 460 is part of a wire-like member, smallanti-migration sleeves 494, 495 may be provided to prevent each knot491, 493 from sliding along the wire. The segment of the sutures 490 a,490 b that extend between the first knots 491 to the loop 492 areaccessible for severing with a blade. The distance between the leafletguard section 460 and sewing band 440 is exaggerated in the drawing, andthe guard section will be desirably be configured to prevent thepossibility of nicking the valve or leaflets with the blade.

In use, the holder 420 and valve 422 are removed from their sterilepackaging in the operating room, and the valve washed or otherwiseprepared for implant. The surgeon may wish to connect a longer handle tothe holder using the handle coupling 472 of the connector 432. A typicalhandle length is between about 6-10 inches. After opening an accesspassage to the aortic valve implant site, the valve 422 is deliveredusing the holder 420 and attached handle.

There are two generally accepted methods for implanting a heart valve.In the first, called the interrupted or parachute suture method, anumber of separate lengths of suture material are pre-anchored in theappropriate places in the native annulus and surrounding tissue. Eachlength loops through the tissue, and thus two free ends extend out ofthe implant site. The two free ends are then threaded throughcorresponding points on the sewing band 440. After all such sutures arepre-threaded through the native tissue and sewing band 440, the valve422 is lowered along the array of sutures into position in the annulus.Each pair of free ends of the sutures is tied off to secure the valve inplace with a plurality of separate one loop suture segments. The secondmethod, called the running suture method, employs one or more suturesthat extend in a series of loops through the native tissue and sewingband 440 for a more continuous structure. The surgeon threads thecontinuous suture through the annulus and valve after delivering thevalve. In this method, visibility of the annulus and surrounding tissuemay be occluded by the valve or holder, and so some manipulation of thevalve and holder structure may be necessary.

Specifically, in the running suture method, the surgeon may manipulatethe valve commissures 426 by flexing them inward along with the holdercommissure supports 436 so as to visualize the implant site under thevalve. Also, the longer handle may be removed from the connector 432 forgreater visibility. As mentioned above, the preferred holder 420 isradially flexible to permit inward flexure and visualization of theimplant site, but desirably resists deformation in either the axial orcircumferential directions. Stiffness in the axial direction helpsprevent excess compression of the valve 422 against the annulus causedby inadvertent excess axial force imparted by the surgeon. Resistance totorsional forces helps maintain the 120° orientation of the commissures426. An added benefit of the radial flexibility of the holder 420 is itsability to be radially compressed to pass through delivery tubes smallerthan the relaxed size of the holder/valve combination.

After attaching the valve to the annulus and ascending aorta using aninterrupted pattern, or one or more continuous stitches, or other suchmeans, the holder 420 is removed. To remove the holder 420, each sutureat the commissures and cusps is severed. For the cusps, the commonsegments 478 of the lengths of suture material 480 (FIG. 29A) extendingalong each leg 444 are severed with one cut. At the commissures, thesegments of suture that extend between the knots 491 and the loop 492are severed, two at a time per commis sure for a total of three cuts.The inwardly bent leaflet guard section 460 prevents the knife bladefrom contacting the leaflets during this operation. Therefore, there area total of four cuts to release the valve from the holder. Each lengthof suture remains attached to the holder, and only free or loosesegments pass through the valve. After severing all sutures, the holdermay be removed from the now implanted valve 422, with the loose segmentsof sutures easily pulling free from the valve sewing band 440.

FIG. 34 illustrates a portion of an alternative valve holder 500 of thepresent invention similar to the holder 420 described above, anddesirably comprising three sire-like pieces. Only a valve contactingportion 502 is shown, along with a plurality of legs 504 extendingbetween cusp supports and a central location, defined by a circle 506drawn in dashed line. Because of this modified arrangement, the innerends 508 of the legs may be secured to the outside of a connectingmember rather than the inside. Also, rather than anti-migration sleevesat the commissures, each leaflet guard section 510 includes a smallanchor point 512, such as a section that is bent in a U-shape.

FIGS. 35 and 36 illustrate a still further holder 520 of the presentinvention having a single wire-like piece that conforms around the cuspsand commissures of the valve 522. The holder 520 includes cusp andcommissure supports but only attaches to the valve 522 at the threecommissures, as indicated in the detail of FIG. 36. Specifically, one ormore lengths of suture may be tied to bent portions of the commissuresupports of the holder, with two shown having relatively more accessiblesevering segments 524 extending between the holder and valve. A separatehandle or connecting member (not shown) may be used, or the holder maybe removed using forceps.

FIGS. 37 and 38 illustrate a one-piece holder 540 and a two-piece holder550, respectively. The holders 540, 550 may be molded pieces of Delrinor other suitable polymer. As before, both holders 540, 550 include cuspand commissure supports, and attach to a heart valve at three or sixlocations. The material is such that inward flexing of the cusp regionsis permitted during the implant operation. In the two piece holder 550,a handle portion 552 along with radial legs 554 may be removed from avalve contacting portion 556 during implant for greater visibility ofthe implant area.

FIG. 39 illustrates a one-piece holder 560 that is similar to theone-piece holder 540 of FIG. 37 but includes a continuous series ofsuture apertures 562 along both the cusp supports 564 and commissuresupports 566. Thus, the holder 560 may be relatively continuouslycoupled to a flexible heart valve to provide more uniform supportthereto. It should also be noted that each leg 568 is molded so as to berelatively circumferentially wider close to the respective cusp support564 than near the handle, and axially thicker near the handle than nearthe cusp support 564. This illustrates the potential for customizing theshape of the holders of the present invention (i.e., by molding) toprovide either flexibility or rigidity in the appropriate places.

FIG. 40 shows a one-piece molded holder 570 that has a handle 572 thatjoins to a single cusp support 574. This arrangement minimizes structurewithin the periphery of the holder 570 and thus maximizes visibility ofthe valve attached thereto. Also, the three cusp supports 574 and threecommissure supports 576 are decoupled and thus have greater flexibilityin the radial direction than earlier embodiments where multiple legsfrom the holder periphery joined at a common point along the centralaxis.

FIGS. 41 and 42 are assembled and exploded views, respectively, of atwo-stage holder 600 of the present invention, along with a flexibleheart valve 602 such as described above. The holder 600 includes arelatively rigid stage 604 coupled to a relatively flexible stage 606with one or more sutures 608. The rigid stage 604 forms a proximal partof the holder and includes a socket 610 for receiving a delivery handle(not shown). Three cusp supports 612 extend at an angle outward anddistally from a base 614 on which the socket 610 resides. One or morecutting guides 616 may be provided on the base 614 over which thesutures 608 are threaded for easy release of the flexible stage 606 fromthe rigid stage 604. In the illustrated embodiment, a single suture 608and single cutting guide 616 are used.

The flexible stage 606 includes three commissure supports 620 thatinclude anchor holes or other such structure to which sutures 622 attachthe supports to the commissures of the valve 602. The commissuresupports 620 are coupled together with three relatively thin bandsegments 624 that permit relative radial flexing of the supports. Ofcourse, other arrangements in which the commissure supports 620 arecoupled together yet remain radially flexible with respect to oneanother are contemplated.

FIGS. 43 and 44 illustrate two modes of use of the holder 600 dependingon the implant method. In the interrupted or parachute method, therelatively rigid stage 604 remains coupled to the relatively flexiblestage 606 during delivery and anchoring of the valve 602. After implant,the sutures 622 holding the commissure supports 620 to the valvecommissures are severed and the holder 600 pulled free. When the runningsuture method is used, the suture 608 is severed at the cutting guide616 thus permitting the relatively rigid stage 604 to be removed, asseen in FIG. 44. The relatively flexible stage 606 remains attached tothe valve 602 with the sutures 622. The arrows 626 illustrate the radialflexibility of the valve commissures as coupled to the relativelyflexible stage 606, which flexibility is permitted by the threerelatively thin band segments 624. Such flexibility helps the surgeonmanipulate the holder/valve combination for greater visibility of theprogress of the running sutures. At the same time, the circumferentialorientation of the three valve commissures (and cusps) is maintained bythe continued attachment of the flexible stage 606. After implant, theflexible stage 606 is removed by severing the sutures 622.

A holder for a highly flexible tissue-type heart valve is disclosed thatmaintains an implant shape to the valve. The holder may have cusp andcommissure contacting supports, and may be attached at all six suchsupports, or only three. The holder may be flexible to permit inwardflexing of the heart valve during implant for greater visibility whenimplanting using a running suture method. The holder may be formed offlexible wires such as Nitinol, and shaped to resist excessive axial andtorsional deformation of the valve. A short handle connector suitablefor manual grasping may be attached and stored with the valve, with thehandle connector having a coupling for receiving a longer deliveryhandle. A two stage holder may be utilized to accommodate differentimplant methods.

The present invention may be embodied in other specific forms withoutdeparting from its spirit or essential characteristics. The describedembodiments are to be considered in all respects only as illustrativeand not restrictive. In particular, though the flexible nature of thepresent heart valve has been described as being particularly suitablefor use in the aortic position, the advantage of flexibility couldequally apply to a valve implanted in other positions, such as themitral position. The scope of the invention is, therefore, indicated bythe appended claims rather than by the foregoing description. Allchanges which come within the meaning and range of equivalency of theclaims are to be embraced within their scope.

1. A heart valve and holder combination, comprising: a flexible heartvalve having multiple leaflets joined together at a periphery of thevalve at valve commissures that are generally axially aligned and evenlydisposed about a valve axis and project toward an outflow end of theheart valve, the valve commissures each being disposed between adjacentcurvilinear valve cusps that are convex toward an inflow end of theheart valve and also arranged around the periphery of the valve; a valveholder having a plurality of straight legs that extend at an outwardangle from a central hub to terminate in cusp supports, the holder beingattached to the heart valve such that the central hub is positionedalong the valve axis on the outflow side of the valve and the legsextend toward the inflow direction between adjacent commissures and thecusp supports contact the heart valve cusps; and a suture securing eachholder cusp support against a respective heart valve cusp, the sutureextending up the leg to an exposed location adjacent the central hub toenable severing by a sharp.
 2. The combination of claim 1, wherein thevalve commissures are radially flexible enabling them to be flexedinward while the holder is attached to the heart valve.
 3. Thecombination of claim 2, wherein the commissures are made of Nitinol. 4.The combination of claim 1, wherein sutures also connect the holder tothe valve commissures.
 5. The combination of claim 4, wherein thesutures connecting the commissures to the holder permit the commissuresto flex.
 6. The combination of claim 4, wherein the holder furtherincludes a plurality of radially extending legs between adjacent cuspsupport legs and terminating in commissure supports, and the suturesconnecting the commissures to the holder secure the commissure supportsto the valve commissures.
 7. The combination of claim 1, wherein thecusp supports each include a concavity on an inflow side for conformingto the respective valve cusp.
 8. A heart valve and holder combination,comprising: a heart valve having multiple leaflets joined together at aperiphery of the valve at valve commissures that are generally axiallyaligned and evenly disposed about a valve axis and project toward anoutflow end of the heart valve, the valve commissures are locatedbetween adjacent curvilinear valve cusps that are convex toward aninflow end of the heart valve and also arranged around the periphery ofthe valve; and a valve holder having a handle socket and plurality oflegs that flare outward at angles therefrom and terminate in cuspsupports, the holder being attached to the heart valve such that thehandle socket is positioned on the outflow side of the valve and thelegs extend toward the inflow direction between adjacent commis suresand the cusp supports contact the heart valve cusps; a suture securingeach holder cusp support against a respective heart valve cusp; and atleast one suture securing each valve commissure to the handle socket. 9.The combination of claim 8, wherein the valve commissures are radiallyflexible enabling them to be flexed inward while the holder is attachedto the heart valve.
 10. The combination of claim 9, wherein thecommissures are made of Nitinol.
 11. The combination of claim 8, whereinthe sutures connecting the commissures to the holder permit thecommissures to flex.
 12. The combination of claim 8, wherein the holderfurther includes a plurality of radially extending legs between adjacentcusp support legs and terminating in commissure supports, and thesutures connecting the commissures to the holder secure the commissuresupports to the valve commissures.
 13. The combination of claim 8,wherein the cusp supports each include a concavity on an inflow side forconforming to the respective valve cusp.
 14. The combination of claim 8,wherein the suture securing each holder cusp support against arespective heart valve cusp extends up the leg to an exposed locationadjacent the handle socket to enable severing by a sharp.
 15. A heartvalve and holder combination, comprising: a flexible heart valve havingthree leaflets joined together at a periphery of the valve at threevalve commissures that are generally axially aligned and evenly disposedabout a valve axis and project toward an outflow end of the heart valve,the valve commissures each being disposed between adjacent curvilinearvalve cusps that are convex toward an inflow end of the heart valve andalso arranged around the periphery of the valve, at least a portion ofthe heart valve being covered by fabric; a valve holder having a centralhub and legs that radiate at an angle outward therefrom; and suturessecuring the valve holder to the heart valve, wherein the sutures passthrough the heart valve fabric at six locations, one at each valve cuspand one at each valve commissure, wherein the legs extend into contactwith the valve cusps and stabilize movement thereby while the valvecommissures are permitted to flex radially relative to the central hub.16. The combination of claim 15, wherein the valve commissures are madeof Nitinol.
 17. The combination of claim 15, wherein the valve holderlegs comprise a plurality of cusp support legs that extend at an outwardangle from the central hub to terminate in cusp supports, the holderbeing attached to the heart valve such that the central hub ispositioned along the valve axis on the outflow side of the valve and thelegs extend toward the inflow direction between adjacent commissures andthe cusp supports contact and conform to the heart valve cusps.
 18. Thecombination of claim 17, wherein the valve holder further includes aplurality of radially extending legs between adjacent cusp support legsand terminating in commissure supports, and the sutures connecting thecommissures to the holder secure the commissure supports to the valvecommissures.
 19. The combination of claim 17, wherein the cusp supportseach include a concavity on an inflow side for conforming to therespective valve cusp.
 20. The combination of claim 17, wherein thesuture securing each holder cusp support against a respective heartvalve cusp extends up the leg to an exposed location adjacent the handlesocket to enable severing by a sharp.